Telescoping stairway for accessing attic storage space

ABSTRACT

A stairway for use in an opening formed between an attic and a floor below comprises a frame adapted to fixedly engage the opening and a plurality of stairway sections operatively coupled to the frame. The stairway sections each have a pair of rails and a plurality of steps coupled between the respective rails. The rails further comprise respective upper and lower edge surfaces having corresponding shapes to permit nesting engagement of the stairway sections on top of each other and relative parallel movement of the stairway sections with respect to each other. Successive ones of the stairway sections are operatively coupled to each other such that they remain nested while being moved relative to each other. Upon reaching an extent of travel relative to each other, orientation of the successive ones of the stairway sections changes to a substantially contiguous and axially aligned structure in which the successive stairway sections are linked end-to-end to provide a continuous stairway. One or more locking pins may be adapted to lock the successive stairway sections in an end-to-end configuration.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to foldable stairs configured forinstallation in an opening between floors of a structure, such as anattic stairway, or more particularly, to an easily deployable stairwaythat permits access to an attic space located above a garage or livingquarters.

2. Description of Related Art

Many homes have attic spaces above garages and living quarters, andthese attic spaces often provide a storage location for various items.While some attic spaces are finished and have access via a fixedstairway, most attic spaces remain unfinished and have more rudimentaryaccess systems. The most basic access system is a simple opening orscuttle hole formed in the ceiling dividing the attic space from theroom below. The scuttle hole is often located above a closet or hallway,and may be covered by a hatch that comprises a removable portion ofceiling, such as formed from plywood or drywall. A user would position aladder below the opening and access the storage space by climbingthrough the scuttle hole.

An improvement over this basic access system is a pull-down or fold-downladder or stairway that is permanently coupled to a hingedly attacheddoor covering the opening. The pull-down stairway may be folded into aplurality of sections to provide a generally compact structure whenstowed. The user opens the door and unfolds the stairway to bring itinto an operational position. This pull-down stairway provides improvedconvenience since the user does not have to transport a ladder to andfrom the access location, and the stairway is anchored to the opening tothereby provide an increased degree of safety for the user. When thestairway is stowed, it does not take up any floor space in the roombelow, in contrast to fixed stairways that take up substantial space.

A drawback of fold-down stairways is that they can be very cumbersome,difficult and unsafe to deploy. Depending upon the height of theceiling, the folded stairway sections may be out of reach for many usersunless another ladder or step stool is used. The user must unfold thestairway by pivoting a substantial portion of its mass while reachingupward often well above the user's head. If the user does not maintain afirm grip on the stairway as it unfolds, the unfolded stairway portionscould inadvertently swing downward and strike the user with significantforce. To return the stairway to the stowed position following use, theuser repeats the same procedure in reverse. These disadvantages make theuse of fold-down stairways impractical and undesirable for many users,particularly older homeowners and women that lack height and sufficientupper body strength.

Thus, it would be advantageous to provide an improved way to deploy anattic stairway easily and safely, while avoiding the disadvantages ofconventional fold-down attic stairways.

SUMMARY OF THE INVENTION

The invention overcomes the disadvantages of conventional fold-downattic stairways by providing a telescoping stairway that deploys withoutunfolding. Instead, the stairway includes plural sections that remainnested while stowed, and deploy by extending axially with respect toeach other and link end-to-end to provide a continuous stairway.

More particularly, an exemplary stairway for use in an opening formedbetween an attic and a floor below comprises a frame adapted to fixedlyengage the opening and a plurality of stairway sections operativelycoupled to the frame. The stairway sections each have a pair of railsand a plurality of steps coupled between the respective rails. The railsfurther comprise respective upper and lower edge surfaces havingcorresponding shapes to permit nesting engagement of the stairwaysections on top of each other and relative parallel movement of thestairway sections with respect to each other. Successive ones of thestairway sections are operatively coupled to each other such that theyremain nested while being moved relative to each other. Upon reaching anextent of travel relative to each other, orientation of the successiveones of the stairway sections changes to a substantially contiguous andaxially aligned structure in which the successive stairway sections arelinked end-to-end to provide a continuous stairway. A locking pin may beadapted to lock the successive stairway sections in an end-to-endconfiguration.

In an embodiment of the invention, the rails of at least one of thestairway sections further include a slot extending substantially anentire length of each associated one of the rails. A slide block isadapted to travel within the slot of a corresponding one of the rails,and a pair of parallel linkages coupled between the slide block and acorresponding one of the rails of a successive one of the stairwaysections. The parallel linkages are oriented in a first direction whenthe successive stairway sections are nested relative to each other andin a second, substantially perpendicular, direction when the successivestairway sections are joined. The pair of parallel linkages may also beare vertically offset with respect to each other. At least one lockingpin may be adapted to lock at least one of the parallel linkages in thesecond direction. The slide block may further include at least oneroller adapted to engage the slot to facilitate low friction movement ofthe slide block within the slot.

In another embodiment of the invention, a door is hingedly attached tothe frame with at least a first one of the stairway sections beingfixedly coupled to the door. A locking finger is operatively coupled tothe frame and oriented to engage a corresponding opening of the door tothereby lock the door in a closed position when the stairway sectionsare stowed. A manual release lever may be adapted to disengage thelocking finger from the opening. Alternatively, a release cable may beadapted to disengage the locking finger from the opening upon deploymentof the stairway sections.

In another embodiment of the invention, at least one slider rail iscoupled to the first one of the stairway sections. The frame furthercomprises a pivot point that slidably engages the at least one sliderrail, wherein the slider rail defines a range of motion of the pluralityof stairway sections in pivoting from a substantially horizontal stowedorientation to a deployed orientation disposed at a predetermined anglefrom horizontal. The slider rail may further comprise an end stopdefining a limit of travel of the slider rail with respect to the pivotpoint. The slider rail may further comprise a temporary stop prior tothe end stop defining an initial angle for deployment of the stairwaysections prior to coming into contact with the floor.

In yet another embodiment of the invention, at least one deploymentcable is associated with each rail of the plurality of stairwaysections. The deployment cable controls relative movement of theplurality of stairway sections such that relative movement in a stairwaydeployment direction is provided by paying out the deployment cable andrelative movement in a stairway stowing direction is provided byretracting the deployment cable. A rotatable drive screw carrying atleast one pulley is engaged with the. Rotation of the drive screw in afirst direction provides paying out of the deployment cable and rotationof the drive screw in a second direction provides retraction of thedeployment cable. An electric motor may be operatively coupled to thedrive screw to enable powered rotation of the drive screw in either thefirst or second directions. The electric motor and the drive screw maybe coupled to the frame, or may be disposed within at least one of theplurality of stairway sections. Alternatively, a removable crank may beadapted to be operatively coupled to the drive screw to enable manualrotation of the drive screw. A pull rope may also be operatively coupledto the drive screw to enable manual rotation of the drive screw. Thepull rope may be adapted to retract when not in use, with a removablehook adapted to retrieve the pull rope when retracted.

In still another embodiment of the invention, the upper edge surfaces ofthe plurality of stairway sections further comprise a generally convexrounded shape, and the lower edge surfaces of the plurality of stairwaysections further comprises a generally concave rounded shaped adapted tonest with the generally convex rounded shape of the upper edge surfaces.The lower edge surfaces of at least one of the plurality of stairwaysections may further comprises at least one roller adapted to enable lowfriction sliding engagement between successive ones of the stairwaysections.

A more complete understanding of the telescoping stairway will beafforded to those skilled in the art, as well as a realization ofadditional advantages and objects thereof, by a consideration of thefollowing detailed description of the preferred embodiment. Referencewill be made to the appended sheets of drawings, which will first bedescribed briefly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of the axially extending stairway in a stowedposition;

FIG. 2 is side view of the stowed stairway taken through the section 2-2of FIG. 1;

FIGS. 3A-3F are side sectional views of the stairway deploymentsequence;

FIG. 4A is a side view of an exemplary drive mechanism for the stairway;

FIGS. 4B1-4B3 are views of an exemplary manual drive mechanism for thestairway, in which FIG. 4B 1 is a side view, FIG. 4B 2 is a partialbottom view, and FIG. 4B 3 shows a drive handle;

FIGS. 4C1-4C2 are side views of another exemplary manual drive mechanismfor the stairway, in which FIG. 4C 1 is a side view and FIG. 4C 2 showsa rope hook;

FIGS. 4D1-4D2 are top views of a drive mechanism as shown in FIG. 4A;

FIG. 5 is a side view of the coupling between the stairway sections;

FIGS. 6A and 6C are views showing one of the stairway section rails, andFIG. 6B is an end sectional view showing the interior of one of theladder rails;

FIG. 7 is a side sectional view of two overlapping stairway sections;

FIG. 8 is an end sectional view of three overlapping stairway sections;

FIG. 9 is an end sectional view of one of the stairway sections showinga locking mechanism for locking two stairway sections together;

FIG. 10 is a side sectional view as taken through the section 10-10 ofFIG. 9;

FIGS. 11A-11C are partial views of the first stairway section showingthe pivot mount block;

FIG. 12 is a top sectional view of the first stairway section rail;

FIG. 13 is a top sectional view of the second stairway section rail;

FIG. 14 is side sectional view of an alternative embodiment of the firststairway section rail;

FIG. 15 is side sectional view of an alternative embodiment of thesecond stairway section rail;

FIGS. 16A-16B are sectional side and perspective views of an end cap forthe first and second stairway section rails showing an alternativelocking mechanism, FIG. 16C is an end sectional view, and FIG. 16D showsa perspective view of the plunger and bolt;

FIG. 17 is a perspective view of an alternative mating end cap for thesecond and third stairway sections;

FIGS. 18A-18B are partial side sectional views of the slider railrelease mechanism, and FIG. 18C in an end sectional view;

FIG. 19 is a side sectional view of an exemplary door release mechanism;

FIGS. 20A-20C are partial sectional views of an alternative stairwaydeployment mechanism;

FIGS. 21A-21C are partial sectional views of an alternative embodimentof the slide block;

FIGS. 22A-22C are partial side and sectional views of an exemplaryhandrail for the stairway sections;

FIG. 23 is a side view of a slider block tether release mechanism; and

FIG. 24 is a side view of an adjustable foot for the third stairwaysection.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

The present invention satisfies the need for an attic stairway that canbe deployed safely and easily without the drawbacks of the conventionalfold-down attic stairways. In the detailed description that follows,like element numerals are used to describe like elements illustrated inone or more figures.

Referring first to FIGS. 1-2, an exemplary attic stairway is shown inaccordance with an embodiment of the invention. The exemplary atticstairway includes a mounting frame 10 formed in a generally rectangularshape having transverse ends and side members. The mounting frame 10 maybe comprised of any suitable material, such as wood, plastic, metal orother high strength, lightweight material capable of supporting asuitable load carried by the stairway. In a preferred embodiment, themounting frame 10 is comprised of a continuous metal strip formed in theappropriate shape and joined at the ends to form a rectangular loop. Themounting frame 10 provides a mechanical structure that supports theother functional components of the attic stairway and provides a surfacefor mounting the attic stairway into a scuttle hole of an attic space(as will be further described below). The scuttle hole is a rectangularopening in the attic floor defined between adjacent joists 201 andheaders 203. Drywall 202 coupled to the undersides of the joists 201 andheaders 203 defines the ceiling of the room below. The mounting frame 10is securely coupled to the joists 201 and headers 203, such as usingnails, lag screws, and the like. The mounting frame 10 may furtherinclude a lip that provides a seal with the scuttle hole and that alsoprovides a decorative border framing the scuttle hole.

The mounting frame 10 carries a plurality of stacked stairway sections.As best shown in FIG. 2, the stairway sections include a first stairwaysection 111, a second stairway section 121, and a third stairway section131. Each stairway section includes a pair of side rails joined by aplurality of steps 114. While in the stowed position, the stairwaysections are nested in engagement with each other. The first stairwaysection 111 is coupled to door 15 using pivot joints 117, which is inturn affixed to the mounting frame 10 via hinge 14. During normaloperation, the pivot joints 117 remain locked in the position shown inFIG. 2, i.e., normal to the door 15. The door 15 may be comprised ofwood, plastic, metal or other suitable material. As will be furtherdescribed below, the door 15 pivots downward as the stairway sectionsdeploy. The door 15 may further include a latch that locks the door 15in a closed position, i.e., substantially flush with the ceiling.

In an embodiment of the invention, the steps 114 may be adapted to snapor bolt into ladder sections 111, 121, and 131. To minimize spacerequired for shipping, it is anticipated that the steps be leftunattached to the ladder sections. The ladder sections 111, 121, and 131would be folded by 90° from its normal (installed) operating position soas to lay parallel to the plane of the door 15 by use of rotatingstowage pivot 151. Alternately, stowage pivot 151 could be substitutedfor a snap-in joint between the door 15 and ladder section 111 toprovide improved packaging efficiency during shipping.

The stairway sections are coupled together by a plurality of slidelinkages. As best shown in FIG. 2, first and second stairway sections111, 121 are coupled by a pair of parallel linkages 113. The linkages113 are rotationally coupled at a first end thereof to a correspondingend of the second stairway section 121, and are rotationally coupled ata second end thereof to a slide block 112. The slide block 112 isdisposed in a corresponding slot that runs the length of the firststairway section 111. Similarly, second and third stairway sections 121,131 are coupled by a pair of parallel linkages 123. The linkages 123 arerotationally coupled at a first end thereof to a corresponding end ofthe third stairway section 131, and are rotationally coupled at a secondend thereof to a slide block 122. The slide block 122 is disposed in acorresponding slot that runs the length of the second stairway section121. Identical slide linkages are located on the other side of thestairway sections (see FIG. 1). The movement and operation of the slidelinkages will be described in further detail below.

Referring briefly to FIG. 5, the coupling between the staircase sections111, 121, 131 is shown in further detail. First and second stairwaysections 111, 121 are axially aligned with the linkages 113 rotatedparallel to the stairway sections. The slide block 112 is located at theend of the slot corresponding to the lowermost end of second stairwaysection 121. Second and third stairway sections 121, 131 are nested ontop of each other with the linkages 123 rotated perpendicular to thestairway sections. The slide block 122 is located at the end of the slotcorresponding to the uppermost end of second stairway section 121. In anembodiment of the invention, one of linkages 113 includes an aperture126 that is aligned with a corresponding pin 127 that forms part ofslide block 112. The pin 127 enters the aperture 126 when the first andsecond stairway sections 111, 121 become axially aligned. Similarly, oneof linkages 123 includes an aperture 124 that is aligned with acorresponding pin 125 that forms part of slide block 122. The pin may beelectrically or mechanically actuated to lock the ladder sections in thedeployed configuration. The second stairway section 121 may furtherinclude a stop 140 comprising a pin having a head that comes intocontact with a corresponding surface of the first stairway section 112.The stop 140 prevents over rotation of the second stairway section 122relative to the first stairway section 112.

In an embodiment of the invention, the stairway sections are deployed bya drive mechanism that includes drive motor 11, drive screw 21, pulleys16, 26 and cables 18, 19 (see FIGS. 1 and 2). The drive motor 11 ismounted to the frame 10 and rotationally drives the drive screw 21.Bracket 12 encloses drive motor 11 and has an opening to permit drivescrew 21 to extend therethrough. Thrust bearing 13 is radially coupledto drive screw 21 and is oriented to contact the surface of bracket 12.A pulley adjust nut 22 is threadingly engaged with the drive screw 21such that the pulley adjust nut moves axially along the length of thedrive screw 21 as the drive screw rotates. Pulley adjust nut bracket 24is carried by the pulley adjust nut 22, and in turn carries a pluralityof adjusting pulleys 26. As will be further described below, theplurality of adjusting pulleys 26 are substantially vertically alignedand share a common axial shaft 25 that is split into two sections toavoid interference with drive screw 21, so that in FIG. 1 they appear asa single pulley. Similarly, cable lengthening pulleys 16 are disposed ata first side of frame 10 and cable guide pulley 17 is disposed at asecond side of the frame. As with the adjusting pulleys 26, the cablelengthening pulleys 16 are vertically aligned and share a common axialshaft 20 (see, e.g., FIG. 2). Pulley 17 is horizontally aligned with theuppermost one of pulleys 16. Cable 18 extends through selected ones ofthe pulleys 16, 26 at a first side of the ladder structure, and cable 19extends to a second side of the ladder structure. The drive mechanismcontrols the paying out of cables 18, 19, which in turn enables thedeployment of the stairway sections.

The exemplary deployment sequence for the stairway sections isillustrated in FIGS. 3A-3F. In FIG. 3A, the stairway is shown in thefully stowed position. The three stairway sections 111, 121, 131 arestacked as described above with respect to FIG. 2. In FIG. 3B, the drivemechanism causes the drive screw 21 to rotate counterclockwise, causingthe tension to increase in the cables 18, 19 (e.g., greater than 75pounds) and thereby release the door latch. The weight of the stairwaysections then cause the door 15 to pivot downward. The drive mechanismcauses the drive screw 21 to rotate clockwise, allowing the cables 18,19 to pay out, thereby positioning the three stairway sections 111, 121,131 at an angle with respect to the floor below. The tension in thecables 18, 19 is greatest when the door 15 is horizontal, and drops tominimum when the door 15 and the first ladder section 111 is fullydeployed (e.g., approximately 27° from vertical).

Each of the stairway sections include corresponding deployment cables.Each of these corresponding deploying cables are in communication withand also exert tension on cables 18 and 19. The tension that each of thecorresponding deployment cables exerts on cables 18 and 19 determinesthe deployment sequence, such that whichever set of cables correspondingto a section of the ladder currently exerts the higher tension on cables18 and 19 will deploy and the other ladder sections will remain in theirrelative positions. In FIG. 3C, as the door 15 and first ladder section111 rotates downward, the tension in cables 18 and 19 caused by in thesecond stairway section deployment cables exceeds that exerted by thefirst ladder section 111. This causes the uppermost two stairwaysections 121, 131 to slide downward together with respect to the firststairway section 111, which remains fixed to the door 15. The twostairway sections 121, 131 continue to slide the length of the firststairway section 111, until eventually the first and second stairwaysections 111, 121 join together at respective ends as shown in FIG. 3D.As will be further described below, a locking mechanism fixes theorientation of stairway sections 111, 121 with respect to each other sothat they form a contiguous rail.

In FIG. 3D, once stairway sections 111 and 121 are in deployed positionwith respect to each other, the tension that the third stairway section131 exerts on deployment cables 18 and 19 becomes greater than thetension caused by the second stairway section, causing the thirdstairway section 131 to slide downward with respect to the secondstairway section 121. The third stairway section 131 continues to deploywith respect to the second stairway section 121 until the second andthird stairway sections 121, 131 join together at respective ends asshown in FIG. 3E. A similar locking mechanism rigidly fixes stairwaysections 121, 131 so that now the first, second and third laddersections form a contiguous rail. After stairway sections 121, 131 arejoined, the tension in cables 18, 19 due to stairway section 131decreases such that the first stairway section 111 exerts the largestforce on cables 18 and 19. This causes the angle of the fully deployedstairway with respect to the floor to once again increase. The entirestairway continues to pivot around the axis defined by the hinge 14,until the bottom of the third stairway section 131 comes to rest withthe floor, as shown in FIG. 3F. To stow the stairway followingdeployment, the above sequence is reversed.

Referring now to FIG. 4A (side view) and FIGS. 4D1-4D2 (top views), anexemplary drive mechanism is shown in greater detail. Cable 19originates at the center of a first cable lengthening pulley 16A and isrouted around first adjusting pulley 26A, then back around the firstcable lengthening pulley 16A, then to a second one of the adjustingpulleys 26B, then back again to a second cable lengthening pulley 16B,and then all the way across the structure to cable guide pulley 17.After passing cable guide pulley 17, cable 19 is redirected parallel tothe side of the frame 10 (see FIG. 1). Cable 18 originates at the centerof a third cable lengthening pulley 16C and is routed around thirdadjusting pulley 26C, then back around the third cable lengtheningpulley 16C, then to a fourth one of the adjusting pulleys 26D, then backagain to a fourth cable lengthening pulley 16D, and then redirectedparallel to the opposite side of the frame 10 (see FIG. 1). In FIGS.4D1-4D2, cable lengthening pulleys 16A-16D are illustrated in staggeredform for convenience of illustration and explanation, but it should beappreciated that the pulleys all share a common axis 20 (as shown inFIG. 4A). Similarly, in FIGS. 4D1-4D2, adjusting pulleys 26A-26D areillustrated in staggered form for convenience of illustration andexplanation, but it should be appreciated that the pulleys all share acommon axis 25 (as shown in FIG. 4A).

With the pulley adjust nut bracket 24 disposed at a right side of thedrive screw 21 (as seen in FIG. 4A), a substantial amount of the slackin cables 18, 19 is taken up by the multiple cable paths between theadjusting pulleys 26 and the cable lengthening pulleys 16. When thedrive motor 11 causes the drive screw 21 to rotate in a clockwisedirection, the pulley adjust nut bracket 24 moves to the left (as seenin FIG. 4A), causing the slack in cables 18, 19 to pay out. Thus, thedrive mechanism produces an extension of cables 18, 19 by a distancethat is a multiple of the corresponding movement of the pulley adjustnut bracket 24. In the embodiment of the invention shown in FIGS.4D1-4D2, a four-times multiple of the cable length is achieved. Itshould be appreciated that greater or smaller multiple cable lengthextensions could be achieved by increasing or decreasing the number ofpulleys.

Returning to FIGS. 1 and 2, a slider rail 116 is pivotably coupled at afirst end to a post 152 that is mounted on pivot mount block 150 that isalso affixed to the first stairway section 111. The slider rail 116 ismovable in an axial direction relative to a slider 339 that remainspivotably fixed to the frame 10. A first deployment pulley 119 iscoupled to the slider 339, and a second deployment pulley 120 is coupledto an end of the slider rail 116. The cable 19 extends from the drivemechanism (discussed above) to the first deployment pulley 119 andredirected to the second deployment pulley 120. Thereafter, the cable 19extends back along the first stairway section 111 and terminates as willbe further described below. Cable 18 follows a similar path on the otherside of the stairway sections. As shown in FIGS. 3A, 3B, as the slack inthe cables 18, 19 increases due to operation of the drive mechanism, thedistance between the two deployment pulleys 119, 120 increases with theslider rail 116 moving axially with respect to the slider 339. As aresult, the door 15 pivots downward, thereby positioning the threestairway sections 111, 121, 131 at an angle with respect to the floorbelow.

An alternative embodiment of the drive mechanism is shown in FIGS.4B1-4B4. As shown in FIG. 4B 1, the motor 11 is replaced with a gearbox27 that includes a first helical gear 28 axially coupled to drive screw21, and second helical gear 29 in mesh with the first helical gear. Thesecond helical gear 29 is axially coupled to a manual drive shaft 30having a receptacle 31. The receptacle 31 extends through the door 15and is substantially enclosed by dust cover 32. FIG. 4B 2 shows thereceptacle 31 from bottom view as including a female key sleeve. FIG. 4B3 shows a suitable crank tool 33 having a male key end 34 (see also FIG.4B 4) having a shape adapted to engage the female key sleeve. The cranktool 33 may further include crank handles 35 facilitating manualrotation of the male key end 34 upon engagement with the female keysleeve of receptacle 31. Rotation of the manual drive shaft 30 therebyproduces corresponding rotation of the drive screw 21 to thereby pay outthe cables 18, 19 in the same manner as described above. A user maythereby enable manual deployment of the stairway sections either insteadof the motor controlled embodiment of FIG. 4A, or as a back-up system tooperate the stairway in the event of loss of electrical power. It shouldbe evident that a modified drive arrangement will allow either the motoror the manual shaft to drive the deployment in the same device.

Another alternative embodiment of the drive mechanism is shown in FIGS.4C1-4C2. As in the preceding embodiment, the motor 11 is replaced with adeploy spool 40 and a stow spool 44 each axially coupled to the drivescrew 21. A length of rope 45 has ends wound onto each of the spools 40,44, forming a loop of rope that passes through an opening in the door15. An internal spring 42 coupled to the deploy spool 40 within abracket 43 causes the deploy spool to wind up the excess rope. Bypulling the rope in a first direction, the deploy spool 40 can be causedto rotate the drive screw 21 and thereby pay out the cables 18, 19 inthe same manner as described above, with the excess rope winding ontothe stow spool. The stairway can be stowed by pulling the rope in theopposite direction. When not in use, the rope will wind onto the deployspool 40 by operation of the internal spring 42. The door 15 is providedwith an indentation 46 that permits capture of the rope using a suitablehook 47 when it is desired to deploy the stairway. Although not shown,it should be evident to those skilled in the art that the rope drivendrive mechanism could be combined with a clutch arrangement such thatthe rope can drive the shaft but not vice versa. This allows the rope tofunction as a backup drive mechanism to deploy the stairway.

Referring now to FIGS. 6A-6C, the first stairway section 111 is shown ingreater detail. FIG. 6A shows a section of a side view of the firststairway section 111 having an axially extending slot in which the slideblock 112 travels (as discussed above). FIG. 6B shows an end view of oneside rail of the first stairway section 111 in cross-section as having arounded top and a generally hollow structure. The side rails of eachstairway section would have generally similar construction and may beformed from extruded aluminum or like materials. The slide block 112includes a rounded edge at upper and lower interior edges that isenclosed by upper and lower lips of the first stairway section 111,thereby holding the slide block within the axial slot. Linkages 113 arerotatably coupled to the slide block by pins 154. As discussed above,the cable 19 passes pulley 120 and is guided into the interior of firststairways section 111 by two successive guide pulleys 163, 165 to atermination point at the back of clevis 168. Clevis 168 has a shaft 162that carries pulleys 160, 161 (described in more detail below). FIG. 6Cshows a side view of the first stairway section 111, including the pathof cable 19 as it passes pulley 120. Pulley 163 is mounted in an openingof the side of first stairway section 111, and guides cable 19 into theinterior of the structure. Pulley 165 is disposed inside the structureof the first stairway section 111, and guides the cable 19 to the clevis168 as discussed above.

FIG. 7 shows the interior construction of the side rails of the firstand second stairway section 111, 121 as taken through a side sectionalview. As discussed above, the cable 19 passes pulley 120 and is guidedinto the interior of first stairway section side rail by two successiveguide pulleys 163, 165 to a termination point 168 at the back of clevis167. Pulleys 163, 165 rotate on respective shafts 164, 166, which areeach in turn fixed to the interior structure of the first stairwaysection 111. Clevis 167 carries pulleys 160, 161, which are alignedaxially on shaft 162. The pulleys 160, 161 control the slack of a secondcable 109 that enables the deployment of the second stairway section121. The first stairway section 111 side rail further includes pulleys175, 177 carried by respective shafts 176, 179 that are mounted to theinterior of the side rail of first stairway section 111. Cable 109originates at pulley 177, then passes around pulley 160, then backaround pulley 177, then to pulley 162, then to pulley 175. Thereafter,the cable 109 exits through an opening in the body of the first stairwaysection side rail and enters a corresponding opening of the secondstairway section side rail. Thus, as the slack in cable 19 is increaseddue to operation of the drive mechanism (described above), pulley 161moves closer to pulleys 175, 177, thereby increasing the slack of cable109 exiting from first stairway section 111.

As with the drive mechanism discussed above, the arrangement of pulleysprovides an extension of cable 109 by a distance that is a multiple ofthe corresponding movement of the clevis 168. In the embodiment of theinvention shown in FIG. 7, a four-times multiple of the cable length isachieved. As will be further described below, the extension of cable 109permits the second stairway section 121 to deploy laterally by force ofgravity with respect to the first stairway section 111, while the firststairway section 111 remains fixed to the door 15.

The second stairway section 121 includes a similar arrangement ofpulleys and cables. After cable 109 enters the opening in the secondstairway section 121, the cable 109 is guided into the interior of thestairway section 121 by guide pulley 186 to a termination point 193 atthe back of clevis 192. Pulley 186 rotates on shaft 190, which is fixedto the interior structure of the second stairway section 121. Clevis 192carries pulley 187 on shaft 191. Pulley 187 controls the slack of athird cable 209 that enables the deployment of the third stairwaysection 131. The second stairway section 121 further includes pulleys188, 189 carried by respective shafts 195, 210. Shaft 195 is movable ina slot 197 against a bias provided by tension in the cables. The shaft210 is fixed to the interior of second stairway section 121. Cable 209originates at movable shaft 195, then passes around pulley 187, thenback around pulley 188, then to pulley 189. Thereafter, the cable 209exits through an opening in the body of the second stairway section 121and enters a corresponding opening of third stairway section 131. Thus,as the payout of cable 109 is increased, pulley 187 moves closer topulley 188, thereby increasing the payout of cable 209 exiting fromsecond stairway section 121. The movable shaft 195 is further coupled tocable 182, that controls a release of a locking mechanism that couplesthe first and second stairway sections 111, 121 together (describedbelow).

The arrangement of pulleys in the second stairway section 121 providesan extension of cable 209 by a distance that is a multiple of thecorresponding movement of the clevis 192. In the embodiment of theinvention shown in FIG. 7, a two-times multiple of the cable length isachieved. As will be further described below, the extension of cable 209permits the third stairway section 131 to deploy laterally by force ofgravity with respect to the second stairway section 121. The cable 209terminates at an end point 198 of the third stairway section 131. Aseparate cable 199 provides a release of a locking mechanism thatcouples the second and third stairway sections 121, 131 together(described below).

FIG. 8 shows an end view of the interior construction of the side railsof the stairway sections 111, 121, 131 in a stacked configuration. Thestairway sections are nested on top of each other, with each having arounded convex top surface and a rounded concave bottom surface.Openings at the top surfaces of the stairway sections permits the cableto pass from one stairway section to another.

FIGS. 9 and 10 illustrate an embodiment of the locking mechanism for oneof the stairway sections. As discussed above with respect to FIG. 5,slide block 122 travels within the axial channel formed in the side ofthe stairway section side rail. The slide block 122 includes an aperturein which a locking pin 127 can extend. The locking pin 127 is pivotallycoupled to a rod 213 using shaft 225. The other end of rod 213 ispivotally coupled to the interior surface of the stairway section usingshaft 215. Spring 216 is coupled at a first end to the rod 213 and at asecond end to the interior surface of the stairway section side rail.The spring 216 bias the locking pin 127 outwardly so that it engages theaperture in the slide block 122 when the linkage 113 has rotated to aposition parallel to the axis of the stairway section side rail (i.e.,when the first and second stairway sections have moved to the alignedorientation). Release cable 219 is guided by rollers 220 and 221, and iscoupled to rod 213. After the locking pin 127 has engaged the apertureof slide block 122, the locking pin 127 can be withdrawn by momentarilypulling on release cable 219.

FIGS. 11A-11C illustrate an embodiment of the stairway section 111showing a pivot mount block 150 having a post 152 that engages theslider rail 116 (discussed above with respect to FIGS. 1 and 2). Thepivot mount block 150 protrudes outwardly of the body of the stairwaysection 111 and carries a mount that secures shaft 164 of guide pulley163. It should be appreciated that using a separate pivot mount block150 facilitates the construction of the stairway section 111 usingconventional extrusion techniques. Alternatively, a unitary constructionthat includes the stairway section 111 and pivot mount block 150 couldalso be advantageously utilized.

FIG. 12 shows the interior construction of an embodiment of the firststairway section 111 as taken through a top sectional view. As discussedabove with respect to FIG. 7, the cable 19 passes pulley 120 and isguided into the interior of the side rail of the first stairway section111 by guide pulleys 163, 165 to a termination point 168 at the back ofclevis 167. The engagement between post 152 and slider rail 116 is alsoshown. Clevis 167 carries pulleys 160, 161, which are aligned axially onshaft 162. The first stairway section 111 further includes pulley 175carried by shaft 176 and pulley 177 carried by shaft 179, each mountedto the interior of first stairway section 111 side rail. Cable 109originates at shaft 176, then passes around pulley 160, then back aroundpulley 177, then to pulley 161, then to pulley 175. Thereafter, thecable 109 exits through an opening in the body of the first stairwaysection 111 as discussed above.

FIG. 13 shows the interior construction of an embodiment of the secondstairway section 121 side rail as taken through a top sectional view.After cable 109 enters the opening in the second stairway section 121,the cable 109 is guided into the interior of the stairway section 121 byguide pulley 186 to a termination point 193 at the back of clevis 192.Pulley 187 carried by clevis 192 controls the slack of third cable 209that enables the deployment of the third stairway section 131. Shaft 195is movable in slot 197. The shaft 210 is fixed to the interior of secondstairway section 121. Cable 209 originates at movable shaft 195, thenpasses around pulley 187, then back around pulley 188, then to pulley189. Thereafter, the cable 209 exits through an opening in the body ofthe second stairway section 121 and enters a corresponding opening ofthird stairway section 131. Thus, as the payout of cable 109 isincreased, pulley 187 moves closer to pulley 188, thereby increasing thepayout of cable 209 exiting from second stairway section 121. Themovable shaft 195 is further coupled to cable 182 that controls arelease of a locking mechanism that couples the first and secondstairway sections 111, 121 together.

Referring now to FIG. 14, an alternative embodiment of the firststairway section 111 is shown through a side sectional view. Asdiscussed above, the cable 19 passes pulley 120 and is guided into theinterior of first stairway section 111 by guide pulley 163 to atermination point at the back of clevis 167. Clevis 167 carries pulley161, which controls the slack of a second cable 109 that enables thedeployment of the second stairway section 121. The first stairwaysection 111 further includes pulleys 281, 283, and 285. Pulley 281 iscarried by shaft 280 that is slidably disposed in axial slot 288.Pulleys 283, 285 are carried by respective shafts 282, 286 that aremounted to the interior of first stairway section 111. Cable 109originates at movable shaft 280, then passes around pulley 161, thenback around pulley 281, then to pulley 283, then to pulley 285.Thereafter, the cable 109 exits through an opening in the body of thefirst stairway section 111. Thus, as the payout of cable 19 is increaseddue to operation of the drive mechanism (described above), pulley 161moves closer to pulley 281, thereby increasing the payout of cable 109exiting from first stairway section 111.

A separate structure controls release of a locking mechanism thatcouples the first and second stairway sections 111, 121 together. Therelease structure includes cable 306 coupled to movable shaft 280,pulleys 307, 308, 309, and lever arm 303. Lever arm 303 is mounted tothe interior of first stairway section 111 at pivot point 305. Cable 306extends from movable shaft 280, around pulley 307, and terminates at anend of lever arm 303. The opposite end of lever arm 303 has cable 316coupled thereto. Cable 316 is guided successively by pulleys 308, 309 tothe locking mechanism (not shown). When tension is applied to cable 19,such as to retract the stairway sections, pulley 281 is caused to moveleftward within slot 288. This transfers tension to cable 306, causingthe lever arm 303 to pivot counterclockwise, in turn causing the cable316 to withdraw and disengage the locking mechanism. Following theinitial tension applied to pulley 281, the pulley 281 will return to theapproximate center of the slot 288 by back tension applied by cable 109.

FIG. 15 shows an alternative embodiment of the second stairway section121 through a side sectional view. After cable 109 enters the opening inthe second stairway section 121, the cable 109 is guided into theinterior of the stairway section 121 by guide pulley 292 to atermination point at the back of clevis 288. Pulley 292 rotates on shaft293, which is fixed to the interior structure of the second stairwaysection 121. Clevis 288 carries pulley 290 on shaft 291. Pulley 290controls the payout of a third cable 294 that enables the deployment ofthe third stairway section 131. The second stairway section 121 furtherincludes pulleys 303, 295, 297 carried by respective shafts 300, 296,298. Shaft 300 is movable in a slot 301 against a bias provided bytension in the cables. The shafts 296, 298 are fixed to the interior ofsecond stairway section 121. Cable 294 originates at movable shaft 195,then passes around pulley 290, then back around pulley 303, thensuccessively to pulleys 295, 297. Thereafter, the cable 294 exitsthrough an opening in the body of the second stairway section 121 andenters a corresponding opening of third stairway section 131 (not shownin FIG. 15). Thus, as the payout of cable 109 is increased, pulley 290moves closer to pulley 303, thereby increasing the payout of cable 294exiting from second stairway section 121. The movable shaft 300 isfurther coupled to cable 302, that controls a release of a lockingmechanism that couples the second and third stairway sections 121, 131together (as described above).

FIG. 15 also shows an exemplary device for taking up any excess payoutin the various deployment cables. Excess payout may be caused by anumber of reasons, such as delay between completion of stairwaydeployment and the termination of the drive motor 11. As shown in FIG.15, a loop 390 pulls on cable 294. Cable 391 is also fastened to thisloop 390 and is guided by roller 392 that is constrained by pin 393 tospring 394. Spring 394 is selected to have a very small spring constantbut with significant stroke so that it can easily take up any excesspayout in cable 294 without otherwise interfering with deployment orstowage of the stairway. A similar arrangement may be utilized to takeup excess slack in the other stairway sections.

An alternative locking mechanism is illustrated in FIGS. 16A-16B. Theexemplary locking mechanism would be formed in an end cap 310 of thefirst and second stairway sections 111, 121. A cylinder housing 314 isprovided within the end cap 310 and includes a corresponding plunger 312that is axially movable within the cylinder housing 314. The plunger 312has an axially coupled bolt 311 aligned with an opening 317 provided atan end of the end cap 310. FIG. 16C illustrates the end cap 310 from anend view, showing the opening 317. FIG. 16D shows the plunger 312 andbolt 311 in a perspective view. The opening 317 is substantially alignedwith a corresponding receptacle of the second or third stairway sections111, 121 (discussed below with respect to FIG. 17). The bolt 311 mayinclude a generally rounded end to facilitate engagement with thereceptacle. Returning to FIGS. 16A-16B, spring 315 is provided in thecylinder housing 314 and is oriented to bias the plunger 312 so that thebolt 311 extends outwardly of the opening 317, thereby locking thestairway section to the next adjacent stairway section. The plunger 312is further coupled to release cable 316 (see FIG. 14) (or the otherrelease cables discussed above). By withdrawing cable 316, the plunger312 and bolt 311 are moved against the bias of spring 315 to therebywithdraw the bolt 311 into the opening 317, and unlock the two stairwaysections. Although the plunger 312 is shown as having a round shape, itshould be appreciated that other shapes could be utilized, such as arectangular shape that would eliminate the bulge in the extrusion thatforms the stairway sections.

FIG. 17 illustrates a mating end cap 320 adapted to engage thecorresponding end cap of FIGS. 16A-16D. The end cap 320 includes areceptacle 322 oriented with respect to the opening 317 to receive thebolt 311 when it extends outwardly of the opening 317. The end cap 320may further include an insert sleeve 321 adapted to insert into theextruded length of the second or third stairway section 121, 131, andmay further include notch 323 corresponding to the axial slot thatcarries the slide block 112. The end cap 320 may further include one ormore mounting holes 324 to carry pulley shafts (as discussed above).

As discussed above, the second and third stairway sections 121, 131connect together to form a contiguous rail before the entire stairwayassembly pivots the final portion before coming to rest on the floor.This portion of the stairway deployment is controlled by a sliderrelease mechanism shown in FIGS. 18A-18C. The slider rail 116 moves upand down relative to a slider release mechanism, and more particularly,the sliding motion relates to the relative distance between the topsurface of slider 339 and the lower surface of stop 330. Pivot joints117 are pivotally mounted to slider 339 and fixedly coupled to the frame10. The stop 330 located at the end of the slider rail 116 defines theend of travel of the slider rail 116 relative to both the top of theslider 339 and the pivot joint 117, at which point the door 15 and thestairway assembly is fully deployed. The slider rail 116 furtherincludes a partial stop defined by a change in width of the slider raila short distance from the stop 330. The partial stop provides a pause inthe deployment of the stairway assembly to permit the second and thirdstairway sections 121, 131 to connect together to form a contiguous railbefore pivoting the final distance to the floor.

More particularly, a slider 339 carries the pivot joint 117 and isadapted to travel along the length of the slider rail 116. The sliderincludes a plunger 331 biased into a retracted position by spring 332.The plunger 331 includes a pin 335 that travels within a slot 336, whichdefines a range of travel of the plunger 331. Release cable 334 controlsthe movement of plunger 331 against the spring bias. The release cable334 is guided by roller 337, passes through an opening in pivot joint117, and terminates at pin 335 of plunger 331. During stairwaydeployment, the tension in release cable 334 pulls the plunger 331against the spring bias into engagement with the partial stop of theslider rail 116. This precludes stop 330 on the slider rail 116 fromdropping thus preventing the stop 330 from being in contact with the topsurface of slider 339 and thus full deployment of the stairway. Afterthe second and third stairway sections 121, 131 have coupled together toform a contiguous rail, the tension in release cable 334 drops so thatit cannot overcome the spring bias, thereby retracting the plunger 331to permit the full extension of the slider rail 116 until stop 330 comesinto contact with the top of slider 339.

Referring now to FIGS. 19-21, an exemplary embodiment of a door releasemechanism is illustrated. As shown in FIG. 19, the stairway sections111, 121 are nested in a stowed configuration with the door 15 closed.The door release mechanism includes a, door release plunger having ahead 70 and shaft 71. The head 70 is aligned with a correspondingreceptacle 85 that is fixed to the door 15. The door release plunger ispivotally arranged relative to pivot point 72 such that, at a first endof travel, the head 70 engages the receptacle 85 (shown in phantom) tothereby lock the door 15. Spring 73 is coupled to the shaft 71 of doorrelease plunger in order to bias the head into engagement with thereceptacle 85. A damper 74 is further coupled to the door releaseplunger via shaft 75 in order to slow the return movement of the plungerfollowing disengagement from the receptacle 85 to permit time for thedoor to open after actuation of the plunger.

The door release plunger can be activated either automatically ormanually. The automatic activation includes release tether 83 that iscoupled to an end of the plunger shaft 71. The release tether 83 isguided by rollers 79, 81. Tension applied to the release tether 83causes the plunger to pivot on pivot point 72 to cause the head 70 torelease from the engagement with the receptacle 85. Thereafter, the head70 will return to the original position by operation of the spring 73and damper 74. The receptacle 85 includes a rounded top surface thatguides the head 70 to engagement with the receptacle when the door 15 isclosed. Manual activation of the plunger is provided by release lever 86that is coupled to plunger head 70 and extends through opening 87 indoor 15. Manual movement of the exposed end of release lever 86 causesthe plunger head 70 to disengage from the receptacle 85.

Referring briefly to FIG. 23, an exemplary cable release mechanism isillustrated for use with both the slider release mechanism of FIGS.18A-18C and the door release mechanism of FIGS. 19-21. As discussedabove, cable 19 (and 18, not shown) controls the deployment of thestairway sections. Cable 19 passes through a pulley 358 having a movableshaft 359 that travels within a slot 360 in bracket 357. To begin thedeployment cycle, the door release mechanism is actuated by operatingthe drive motor 11 in the stow (reverse) direction. This causes thecables 19 (and 18) to lift pulley 358 and shaft 359 within the slot 360.The movable shaft 359 retracts cable 83 that triggers the door releasemechanism to release the door 15. Once the door has released, thedirection of motor 11 is reversed, such as activation by a suitablecontroller or more simply by a micro-switch engaged with the door 15.This allows the cable 19 (and cable 18) to begin to pay out.

While the three stairway sections are deploying, tension in cable 19remains high while nevertheless still being much lower than thatrequired to release the door 15. This deployment action also keeps cable83 retracted. Cable 83 branches off to spring 380 at one end and cable334 coupled to the far end of the spring. During deployment, the tensionin cable 19 exerts force on spring 380 and cable 334, and ultimatelyovercomes the spring bias applied by spring 332 to prevent fulldeployment of the slider rail 116. As discussed earlier, when all threestairway sections are fully aligned and locked, the tension in cable 19and spring 380 and cable 334 in direct communication is reduced to alevel that is lower than the bias of the spring 332, thus allowing fullextension of slider rail 116 to complete the deployment of the stairway.The purpose of spring 380 is to allow cable 83 to fully retract upon theinitial deployment sequence (and following the plunger 331 being fullyextended against the slider rail 116), thus allowing the door releasemechanism to function properly. Accordingly, the spring constant (force)of spring 380 is selected to be much higher than that of spring 332 sonot to disrupt the normal function of spring 332 that is intended tooperate with lower cable forces.

FIG. 18C shows the slider 339 in cross-section in relation to themounting frame 10. As discussed above with respect to FIGS. 1 and 2, thepivot joints 117 are supported by bracket 341 and are also pivotallymounted to the slider 339. In addition, the pivot joints 117 alsocarries deployment pulley 119 used to guide cable 19. Accordingly,deployment pulley 119 moves along slider rail 116 in cooperation withslider 339.

An alternative stairway deployment mechanism is shown in FIGS. 20A-20C.Unlike the preceding embodiment, the motor drive mechanism used to varythe deployment cable tension is contained entirely within individualones of the stairway sections. FIG. 20B shows a side cross-section ofthe three stairway sections 111, 121, 131 side rails in the fully stowedor stacked configuration. Stairway section 121 side rail includes aroller 355 that rotates on axle 356, which is oriented to engage anupper surface of stairway section 111 to enable stairway section 121 tomove in an axial direction relative to stairway section 111 (see alsoFIG. 20A). The stairway sections otherwise deploy and retract in thesame manner as described above.

Stairway section 121 is further shown as including motor 230 and drivescrew 231. The motor 230 is mounted to the interior of stairway section121 and rotationally drives the drive screw 231. The opposite end ofdrive screw 231 turns within mount 232. A pulley adjust nut 233 isthreadingly engaged with the drive screw 231 such that the pulley adjustnut moves axially along the length of the drive screw 231 as the drivescrew rotates. Pulley adjust nut bracket 234 is carried by the pulleyadjust nut 233, and in turn carries upper pulley 238 and lower pulley245. Upper pulley 238 controls the paying out of cable 242 that enablesthe deployment of the third stairway section 131. Pulleys 236, 237 arefixedly mounted within the stairway section 121 and share a common axle241. Cable 242 originates at the pulley adjust nut bracket 234, extendsaround pulley 236, back to upper pulley 238, then back around pulley237, after which the cable 242 exits the stairway section 121 andengages stairway section 131. With the pulley adjust nut bracket 234disposed relatively close to the motor 230, the slack in the cable 242is taken up by the paths between the pulleys 236, 237 and pulley 238.Operation of the motor 230 causes the pulley adjust nut bracket 234 tomove and thereby take up the slack in the cable 242. Thus, the drivemechanism produces an extension of cable 242 by a distance that is amultiple of the corresponding movement of the pulley adjust nut bracket234. It should be appreciated that the first stairway section 111 wouldhave a similar deployment mechanism to facilitate relative deployment ofthe second stairway section 121.

The lower pulley 245 serves to drive a corresponding mechanism locatedin the opposite side rail of the stairway section 121. Morespecifically, the opposite side rail includes a similar mechanism with adrive screw and pulley adjust nut bracket carrying an upper and lowerpulley, though it does not include a motor. Instead, the lower pulley245 shown in FIG. 20B cooperates with pulleys 243, 248 to pay out adriving cable 247 that extends across the stairway to the other siderail, where it drives a corresponding arrangement of pulleys. Inparticular, driving cable 247 originates at the pulley adjust nutbracket 234, extends to pulley 243, then back around lower pulley 245,then back to pulley 248 then across to crossover pulley 239. The drivingcable 247 then exits the stairway section 121 and crosses over to theother side rail of the stairway. Then, the driving cable 247 enters intothat opposite side stairway section rail and engages a similar set ofpulleys. Thus, as motor 230 causes the slack in driving cable 247 to bedrawn in, i.e., when the third stairway section is being drawn in forstowage, the tension in driving cable 247 will cause the pulley adjustnut bracket in the opposite rail to move in a cooperative manner.Accordingly, there is no need for a motor in the opposite side rail ofthe stairway section.

An alternative embodiment of the slide block used to join adjacentstairway section rails is shown in FIGS. 21A-21C. A slide block plate350 carries a plurality of rollers 351 that rotate on respective axles352. The rollers 351 are located adjacent the peripheral corner regionsof the slide block plate 350 such that an outer portion of each rollerextends beyond the periphery of the slide block plate. Linkage pivotpins 128 extend perpendicularly from the surface of the slide blockplate 35 to enable engagement with linkages (not shown) that couple toan adjacent stairway section rail (as discussed above with respect toFIG. 5). The slide block plate 350 is adapted to travel axially within aslot formed in the side of the stairway section rail, such as stairwaysection rail 121 shown in FIG. 21C. The rollers 351 engage the top andbottom edges of the slot to provide a low friction engagement formovement of the slide block relative to the stairway section rail.Contact surfaces 353 provide additional structural support when therollers 351 are overloaded, such as when the stairway is in use afterbeing fully deployed.

FIGS. 22A-22C illustrate an exemplary handrail for the stairwaysections. The handrail includes an upper handrail 260 and a lowerhandrail 261 mounted to the first stairway section 111. The upper andlower handrails 260, 261 each comprise a generally S-shaped crosssection having a mounting portion that couples to the underside of thefirst stairway section 111 and a gripping portion that provides asurface adapted to be grasped by a user while climbing the deployedstairway. A space between the upper and lower handrails 260, 261 enablesmovement of the slider rail 116 discussed above. FIG. 22B shows thehandrail and stairway sections in a stowed configuration, and FIG. 22Cshows the handrail and stairway sections in a partially deployedconfiguration. Note that slider rail 116 is not shown in this figure forsimplicity. It should be appreciated that a similar handrail may bedisposed on the other side of the stairway sections.

Lastly, FIG. 24 illustrates an adjustable foot 364 adapted to engage anend of the third stairway section 131. The adjustable foot 364 enablesthe length of the deployed stairway sections to be adjusted toaccommodate the particular floor to ceiling height of the room in whichthe stairway is deployed. The foot 364 is coupled to an insert 365 thatextends into the end of the third stairway section 131. The insert 365may include a plurality of adjustment holes aligned with a screw 368that engages the third stairway section 131 and a selected one of theadjustment holes. The foot 364 may further be provided with a highfriction end surface to reduce slippage of the bottom of the thirdstairway section 131 relative to the floor.

It should be appreciated by those skilled in the art that micro-switchesor other like devices that can sense position could be placed in keypositions on the stairway to aid in the deployment sequence. Morespecifically, one or more micro-switches may be positioned to close whenthe hinge 14 is in the horizontal position and thus the ladder isstowed. Yet another micro-switch could be positioned to close when hinge14 is in the maximum rotated position, such that it is fully deployedapproximately 27° from the vertical. Other micro-switches may bepositioned in locations that allow detection that bolts 311 are in thelocked position indicating that the first-to-second stairway sectionsand second-to-third stairway sections are fully deployed and lockedtogether. Additional micro-switches or sensors may be located to sensethe door release mechanism position, such as via the position of cable83 and under the foot of the ladder 364. The above micro-switches and/orsensors could be coupled to a central control unit that receives userinput to activate the drive motor 11. Alternately, the micro-switchesmay provide position feedback that provides an input used to triggeraudible or visual alarms, including lights or colored LEDs, such as toindicate deployment status of the stairway. It is further anticipatedthat the micro-switches or sensors could be positioned at theappropriate locations on both sides of the stairway. It is furtheranticipated that a mechanical linkage from the lower stairway sectionsmay trigger a micro-switch on the first stairway section 111, such asusing a protruding pin that is in communication with the bolt 311positioned in the corresponding lower section of the stairway. Thisapproach would be advantageous by eliminating (a) the potential forbinding of electrical wires across the stairway sections, (b) the needfor independent power sources for each stairway section, and/or (c)corrosion of electrical connectors that provide electrical connectivitybetween the stairway sections.

Having thus described a preferred embodiment of a telescoping atticstairway, it should be apparent to those skilled in the art that certainadvantages have been achieved. It should also be appreciated thatvarious modifications, adaptations, and alternative embodiments thereofmay be made within the scope and spirit of the present invention. Theinvention is defined solely by the following claims.

1. A stairway for use in an opening formed between an attic and a floorbelow, comprising: a frame adapted to fixedly engage the opening; aplurality of stairway sections operatively coupled to the frame and eachhaving a pair of rails and a plurality of steps coupled between therespective rails, the rails further comprising respective upper andlower edge surfaces having corresponding shapes to permit nestingengagement of the stairway sections on top of each other and relativeparallel movement of the stairway sections with respect to each other;wherein, successive ones of the stairway sections are operativelycoupled to each other such that they remain nested while being movedrelative to each other, and upon reaching an extent of travel relativeto each other, orientation of the successive ones of the stairwaysections changes to a substantially contiguous and axially alignedstructure in which the successive stairway sections are linkedend-to-end to provide a continuous stairway.
 2. The stairway of claim 1,wherein the rails of at least one of the stairway sections furtherinclude a slot extending substantially an entire length of eachassociated one of the rails.
 3. The stairway of claim 2, furthercomprising a slide block adapted to travel within the slot of acorresponding one of the rails, and a pair of parallel linkages coupledbetween the slide block and a corresponding one of the rails of asuccessive one of the stairway sections, the parallel linkages beingoriented in a first direction when the successive stairway sections arenested relative to each other and in a second, substantiallyperpendicular, direction when the successive stairway sections arejoined.
 4. The stairway of claim 3, wherein the pair of parallellinkages are vertically offset with respect to each other.
 5. Thestairway of claim 3, further comprising at least one locking pin adaptedto lock at least one of the parallel linkages in the second direction.6. The stairway of claim 3, wherein the slide block further comprises atleast one roller adapted to engage the slot to facilitate low frictionmovement of the slide block within the slot.
 7. The stairway of claim 1,further comprising a door hingedly attached to the frame, at least afirst one of the stairway sections being fixedly coupled to the door. 8.The stairway of claim 7, further comprising a locking finger operativelycoupled to the frame and oriented to engage a corresponding opening ofthe door to thereby lock the door in a closed position when the stairwaysections are stowed.
 9. The stairway of claim 8, further comprising amanual release lever adapted to disengage the locking finger from theopening.
 10. The stairway of claim 8, further comprising a release cableadapted to disengage the locking finger from the opening upon deploymentof the stairway sections.
 11. The stairway of claim 7, furthercomprising a pivot joint coupling the rails of the first one of thestairway sections to the door, the pivot joint permitting the rails ofthe stairway sections to be folded parallel to the door to provide acompact profile.
 12. The stairway of claim 1, wherein the steps areselectively detachable from the rails.
 13. The stairway of claim 1,further comprising at least one slider rail coupled to the first one ofthe stairway sections, the frame further comprising a pivot point thatslidably engages the at least one slider rail, wherein the slider raildefines a range of motion of the plurality of stairway sections inpivoting from a substantially horizontal stowed orientation to adeployed orientation disposed at a predetermined angle from horizontal.14. The stairway of claim 13, wherein the at least one slider railfurther comprises an end stop defining a limit of travel of the sliderrail with respect to the pivot point.
 15. The stairway of claim 14,wherein the at least one slider rail further comprises a temporary stopprior to the end stop defining an initial angle for deployment of thestairway sections prior to coming into contact with the floor.
 16. Thestairway of claim 1, further comprising at least one deployment cableassociated with each rail of the plurality of stairway sections, the atleast one deployment cable controlling relative movement of theplurality of stairway sections such that relative movement in a stairwaydeployment direction is provided by paying out the at least onedeployment cable and relative movement in a stairway stowing directionis provided by retracting the at least one deployment cable.
 17. Thestairway of claim 16, further comprising a rotatable drive screwcarrying at least one pulley engaged with the at least one deploymentcable, wherein rotation of the drive screw in a first direction providespaying out of the at least one deployment cable and rotation of thedrive screw in a second direction provides retraction of the at leastone deployment cable.
 18. The stairway of claim 17, further comprisingan electric motor operatively coupled to the drive screw to enablepowered rotation of the drive screw in selected ones of the first andsecond directions.
 19. The stairway of claim 18, wherein the electricmotor and the drive screw are coupled to the frame.
 20. The stairway ofclaim 18, wherein the electric motor and the drive screw are disposedwithin at least one of the plurality of stairway sections.
 21. Thestairway of claim 17, further comprising a removable crank adapted to beoperatively coupled to the drive screw to enable manual rotation of thedrive screw in selected ones of the first and second directions.
 22. Thestairway of claim 17, further comprising a pull rope operatively coupledto the drive screw to enable manual rotation of the drive screw inselected ones of the first and second directions.
 23. The stairway ofclaim 22, wherein the pull rope is adapted to retract when not in use.24. The stairway of claim 23, further comprising a removable hookadapted to retrieve the pull rope when retracted.
 25. The stairway ofclaim 17, further comprising a control circuit adapted to controloperation of the electric motor.
 26. The stairway of claim 25, whereinthe control circuit includes at least one micro-switch adapted to sensea deployment condition of at least one of the stairway sections.
 27. Thestairway of claim 1, wherein the plurality of stairway sections furthercomprises at least three stairway sections.
 28. The stairway of claim 1,wherein the plurality of stairway sections further comprises at leasttwo stairway sections.
 29. The stairway of claim 1, further comprisingat least one locking pin adapted to lock the successive stairwaysections in an end-to-end configuration.
 30. The stairway of claim 1,wherein the upper edge surfaces of the plurality of stairway sectionsfurther comprises a generally convex rounded shape, and the lower edgesurfaces of the plurality of stairway sections further comprises agenerally concave rounded shaped adapted to nest with the generallyconvex rounded shape of the upper edge surfaces.
 31. The stairway ofclaim 1, wherein the lower edge surfaces of at least one of theplurality of stairway sections further comprises at least one rolleradapted to enable low friction sliding engagement between successiveones of the stairway sections.
 32. The stairway of claim 1, furthercomprising at least one handrail coupled to at least one of theplurality of stairway sections.
 33. The stairway of claim 1, wherein oneof the plurality of stairway sections adapted to come into contact withthe floor further comprises an adjustable foot.